Question regarding Heat Transfer in Carnot Engine

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SUMMARY

The discussion centers on the mechanics of heat transfer in a Carnot Engine, emphasizing that heat transfer occurs only during isothermal processes. It highlights that if the working material's temperature is not aligned with the hot reservoir, heat is irreversibly lost to achieve thermal equilibrium. The conversation also clarifies that the work done by the engine is calculated as the difference between the heat supplied by the hot reservoir (Q_H) and the heat rejected to the cold reservoir (Q_C). Additionally, it confirms that the adiabatic process in the Carnot cycle serves to complete the cycle, despite the challenges of physically achieving such conditions.

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  • Knowledge of isothermal and adiabatic processes
  • Familiarity with thermodynamic cycles
  • Basic grasp of heat transfer concepts
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  • Explore the differences between isothermal and adiabatic processes
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Harikesh_33
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***A Carnot Engine*** is a theoretical engine unlike a Sterling Engine which can be made practically.

Some of the drawbacks of Carnot Engine are,

1)The Heat Transfer occurs only during isothermal process(compression and expansion),this is because the working material (ie) gas or fuel used, if it's at a different temperature(technically the temperature of the working material is infinitesimally smaller)than the hot reservoir ,then some amount of heat get's used up to attain thermal equilibrium (ie) it's irreversibly lost .

Now my question is ,if ##Q_H## is the heat supplied by the #Heat# #Reservoir# ,then the heat is used to do some work of say ##dW=pdV## and if entire heat ##Q_H## gets used as Work, then how does it transfer ##Q_c## amount of heat to the cold reservoir?

And it seems so odd to say that once the Isothermal processes are over ,it expands /contracts adiabatically ,are we physically removing the sources here ? **Is the only use of Adiabatic process in ***"Imaginary Carnot Cycle"*** to produce a proper cycle**?
 
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Harikesh_33 said:
Now my question is ,if ##Q_H## is the heat supplied by the #Heat# #Reservoir# ,then the heat is used to do some work of say ##dW=pdV## and if entire heat ##Q_H## gets used as Work, then how does it transfer ##Q_c## amount of heat to the cold reservoir?
The amount of work is ##Q_H - Q_C##, not just ##Q_H##.

Harikesh_33 said:
are we physically removing the sources here ? **Is the only use of Adiabatic process in ***"Imaginary Carnot Cycle"*** to produce a proper cycle**?
Yes, you are shutting down the heat transfer process, Something similar to closing a valve to shut down a mass flow. Something very difficult to achieve physically, most likely impossible at high speed.
 
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